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Parameters optimization of terahertz negative dynamic conductivity in optically and electrically pumped graphene structures

LIU YA-QING1, REN GUANG-JUN1,* , ZHANG YU-PING2, CAO YAN-YAN2, ZHANG HUI-YUN2

Affiliation

  1. School of Electronics Information Engineering; Tianjin Key Lab. Of Film Electronic & Communication Devices; Engineering Research Center of Communication Devices and Technology, Ministry of Education;
  2. Qingdao Key Laboratory of Terahertz Technology, College of Science, Shandong University of Science and Technology, Qingdao 266510, PR China

Abstract

We study parameters optimization of negative dynamic conductivity in terahertz range of frequencies in optically and electrically pumped graphene structures. Graphene structures consist of single-graphene-layer (SGL) structures and multiple-structure-layer (MGL) structures. The optimization of parameters including quasi-Femi energy, effective temperature, electron-hole momentum relaxation time and the number of graphene layer (GL) etc. were studied systematically. From the simulations we find that the negative dynamic conductivity in optically pumped graphene structures can be largest when effective temperature T  50K , relaxation time 10ps , quasi-Femi energy 55 F   meV and the number of GL K 120 . The negative dynamic conductivity in electrically pumped graphene structures can be largest when T  50K , 10ps , bias voltage V 120meV and low gate voltage. Meanwhile, the negative dynamic conductivity can be larger in electrically pumped graphene structures than that in optically pumped graphene structures..

Keywords

Terahertz, Graphene, Negative dynamic conductivity, Parameters optimization.

Submitted at: Aug. 25, 2014
Accepted at: May 7, 2015

Citation

LIU YA-QING, REN GUANG-JUN, ZHANG YU-PING, CAO YAN-YAN, ZHANG HUI-YUN, Parameters optimization of terahertz negative dynamic conductivity in optically and electrically pumped graphene structures, Journal of Optoelectronics and Advanced Materials Vol. 17, Iss. 5-6, pp. 675-680 (2015)